Integrated haptic system

ABSTRACT

An integrated haptic system may include a digital signal processor and an amplifier communicatively coupled to the digital signal processor and integrated with the digital signal processor into the integrated haptic system. The digital signal processor may be configured to receive a force sensor signal indicative of a force applied to a force sensor and generate a haptic playback signal responsive to the force. The amplifier may be configured to amplify the haptic playback signal and drive a vibrational actuator communicatively coupled to the amplifier with the haptic playback signal as amplified by the amplifier.

RELATED APPLICATION

The present disclosure claims priority to U.S. Provisional PatentApplication Ser. No. 62/503,163, filed May 8, 2017, and U.S. ProvisionalPatent Application Ser. No. 62/540,921, filed Aug. 3, 2017, both ofwhich are incorporated by reference herein in their entirety.

FIELD OF DISCLOSURE

The present disclosure relates in general to electronic devices withuser interfaces, (e.g., mobile devices, game controllers, instrumentpanels, etc.), and more particularly, an integrated haptic system foruse in a system for mechanical button replacement in a mobile device,for use in haptic feedback for capacitive sensors, and/or other suitableapplications.

BACKGROUND

Linear resonant actuators (LRAs) and other vibrational actuators (e.g.,rotational actuators, vibrating motors, etc.) are increasingly beingused in mobile devices (e.g., mobile phones, personal digitalassistants, video game controllers, etc.) to generate vibrationalfeedback for user interaction with such devices. Typically, aforce/pressure sensor detects user interaction with the device (e.g., afinger press on a virtual button of the device) and in response thereto,the linear resonant actuator vibrates to provide feedback to the user.For example, a linear resonant actuator may vibrate in response to forceto mimic to the user the feel of a mechanical button click.

One disadvantage of existing haptic systems is that existing approachesto processing of signals of a force sensor and generating of a hapticresponse thereto often have longer than desired latency, such that thehaptic response may be significantly delayed from the user's interactionwith the force sensor. Thus, in applications in which a haptic system isused for mechanical button replacement, capacitive sensor feedback, orother application, and the haptic response may not effectively mimic thefeel of a mechanical button click. Accordingly, systems and methods thatminimize latency between a user's interaction with a force sensor and ahaptic response to the interaction are desired.

In addition, to create appropriate and pleasant haptic feelings for auser, a signal driving a linear resonant actuator may need to becarefully designed and generated. In mechanical button replacementapplication, a desirable haptic response may be one in which thevibrational impulse generated by the linear resonant actuator should bestrong enough to give a user prominent notification as a response tohis/her finger pressing and/or releasing, and the vibrational impulseshould be short, fast, and clean from resonance tails to provide a usera “sharp” and “crisp” feeling. Optionally, different control algorithmsand stimulus may be applied to a linear resonant actuator, to alter theperformance to provide alternate tactile feedback—possibly denotingcertain user modes in the device—giving more “soft” and “resonant”tactile responses.

SUMMARY

In accordance with the teachings of the present disclosure, thedisadvantages and problems associated with haptic feedback in a mobiledevice may be reduced or eliminated.

In accordance with embodiments of the present disclosure, an integratedhaptic system may include a digital signal processor and an amplifiercommunicatively coupled to the digital signal processor and integratedwith the digital signal processor into the integrated haptic system. Thedigital signal processor may be configured to receive an input signalindicative of a force applied to a force sensor and generate a hapticplayback signal responsive to the input signal. The amplifier may beconfigured to amplify the haptic playback signal and drive a vibrationalactuator communicatively coupled to the amplifier with the hapticplayback signal as amplified by the amplifier.

In accordance with these and other embodiments of the presentdisclosure, a method may include receiving, by a digital signalprocessor, an input signal indicative of a force applied to a forcesensor. The method may also include generating, by the digital signalprocessor, a haptic playback signal responsive to the input signal. Themethod may further include driving, with an amplifier communicativelycoupled to the digital signal processor and integrated with the digitalsignal processor into an integrated haptic system, the haptic playbacksignal as amplified by the amplifier.

In accordance with these and other embodiments of the presentdisclosure, an article of manufacture may include a non-transitorycomputer-readable medium computer-executable instructions carried on thecomputer-readable medium, the instructions readable by a processor, theinstructions, when read and executed, for causing the processor toreceive an input signal indicative of a force applied to a force sensorand generate a haptic playback signal responsive to the input signal,such that an amplifier communicatively coupled to the processor andintegrated with the digital signal processor into an integrated hapticsystem, amplifies and drives the haptic playback signal.

Technical advantages of the present disclosure may be readily apparentto one having ordinary skill in the art from the figures, descriptionand claims included herein. The objects and advantages of theembodiments will be realized and achieved at least by the elements,features, and combinations particularly pointed out in the claims.

It is to be understood that both the foregoing general description andthe following detailed description are examples and explanatory and arenot restrictive of the claims set forth in this disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete understanding of the present embodiments and advantagesthereof may be acquired by referring to the following description takenin conjunction with the accompanying drawings, in which like referencenumbers indicate like features, and wherein:

FIG. 1 illustrates a block diagram of selected components of an examplemobile device, in accordance with embodiments of the present disclosure;

FIG. 2 illustrates a block diagram of selected components of an exampleintegrated haptic system, in accordance with embodiments of the presentdisclosure;

FIG. 3 illustrates a block diagram of selected components of an exampleprocessing system for use in the integrated haptic system of FIG. 2, inaccordance with embodiments of the present disclosure;

FIG. 4 illustrates a block diagram of selected components of anotherexample integrated haptic system, in accordance with embodiments of thepresent disclosure;

FIG. 5 illustrates a graph showing example waveforms of haptic drivingsignals that may be generated, in accordance with embodiments of thepresent disclosure;

FIG. 6 illustrates a graph depicting an example transfer function ofdisplacement of linear resonant actuator as a function of frequency at avoltage level equal to a maximum static excursion occurring at lowfrequencies, in accordance with embodiments of the present disclosure;

FIG. 7 illustrates a graph depicting an example transfer function ofacceleration of linear resonant actuator as a function of frequency anda maximum acceleration at maximum excursion, in accordance withembodiments of the present disclosure;

FIG. 8 illustrates a block diagram of selected components of anotherexample integrated haptic system, in accordance with embodiments of thepresent disclosure;

FIG. 9 illustrates a block diagram of selected components of anotherexample integrated haptic system, in accordance with embodiments of thepresent disclosure;

FIG. 10 illustrates a block diagram of selected components of anotherexample integrated haptic system, in accordance with embodiments of thepresent disclosure; and

FIG. 11 illustrates a block diagram of selected components of anotherexample integrated haptic system, in accordance with embodiments of thepresent disclosure.

DETAILED DESCRIPTION

FIG. 1 illustrates a block diagram of selected components of an examplemobile device 102, in accordance with embodiments of the presentdisclosure. As shown in FIG. 1, mobile device 102 may comprise anenclosure 101, a controller 103, a memory 104, a force sensor 105, amicrophone 106, a linear resonant actuator 107, a radiotransmitter/receiver 108, a speaker 110, and an integrated haptic system112.

Enclosure 101 may comprise any suitable housing, casing, or otherenclosure for housing the various components of mobile device 102.Enclosure 101 may be constructed from plastic, metal, and/or any othersuitable materials. In addition, enclosure 101 may be adapted (e.g.,sized and shaped) such that mobile device 102 is readily transported ona person of a user of mobile device 102. Accordingly, mobile device 102may include but is not limited to a smart phone, a tablet computingdevice, a handheld computing device, a personal digital assistant, anotebook computer, a video game controller, or any other device that maybe readily transported on a person of a user of mobile device 102.

Controller 103 may be housed within enclosure 101 and may include anysystem, device, or apparatus configured to interpret and/or executeprogram instructions and/or process data, and may include, withoutlimitation a microprocessor, microcontroller, digital signal processor(DSP), application specific integrated circuit (ASIC), or any otherdigital or analog circuitry configured to interpret and/or executeprogram instructions and/or process data. In some embodiments,controller 103 interprets and/or executes program instructions and/orprocesses data stored in memory 104 and/or other computer-readable mediaaccessible to controller 103.

Memory 104 may be housed within enclosure 101, may be communicativelycoupled to controller 103, and may include any system, device, orapparatus configured to retain program instructions and/or data for aperiod of time (e.g., computer-readable media). Memory 104 may includerandom access memory (RAM), electrically erasable programmable read-onlymemory (EEPROM), a Personal Computer Memory Card InternationalAssociation (PCMCIA) card, flash memory, magnetic storage, opto-magneticstorage, or any suitable selection and/or array of volatile ornon-volatile memory that retains data after power to mobile device 102is turned off.

Microphone 106 may be housed at least partially within enclosure 101,may be communicatively coupled to controller 103, and may comprise anysystem, device, or apparatus configured to convert sound incident atmicrophone 106 to an electrical signal that may be processed bycontroller 103, wherein such sound is converted to an electrical signalusing a diaphragm or membrane having an electrical capacitance thatvaries as based on sonic vibrations received at the diaphragm ormembrane. Microphone 106 may include an electrostatic microphone, acondenser microphone, an electret microphone, a microelectromechanicalsystems (MEMS) microphone, or any other suitable capacitive microphone.

Radio transmitter/receiver 108 may be housed within enclosure 101, maybe communicatively coupled to controller 103, and may include anysystem, device, or apparatus configured to, with the aid of an antenna,generate and transmit radio-frequency signals as well as receiveradio-frequency signals and convert the information carried by suchreceived signals into a form usable by controller 103. Radiotransmitter/receiver 108 may be configured to transmit and/or receivevarious types of radio-frequency signals, including without limitation,cellular communications (e.g., 2G, 3G, 4G, LTE, etc.), short-rangewireless communications (e.g., BLUETOOTH), commercial radio signals,television signals, satellite radio signals (e.g., GPS), WirelessFidelity, etc.

A speaker 110 may be housed at least partially within enclosure 101 ormay be external to enclosure 101, may be communicatively coupled tocontroller 103, and may comprise any system, device, or apparatusconfigured to produce sound in response to electrical audio signalinput. In some embodiments, a speaker may comprise a dynamicloudspeaker, which employs a lightweight diaphragm mechanically coupledto a rigid frame via a flexible suspension that constrains a voice coilto move axially through a cylindrical magnetic gap. When an electricalsignal is applied to the voice coil, a magnetic field is created by theelectric current in the voice coil, making it a variable electromagnet.The coil and the driver's magnetic system interact, generating amechanical force that causes the coil (and thus, the attached cone) tomove back and forth, thereby reproducing sound under the control of theapplied electrical signal coming from the amplifier. Force sensor 105may be housed within enclosure 101, and may include any suitable system,device, or apparatus for sensing a force, a pressure, or a touch (e.g.,an interaction with a human finger) and generating an electrical orelectronic signal in response to such force, pressure, or touch. In someembodiments, such electrical or electronic signal may be a function of amagnitude of the force, pressure, or touch applied to the force sensor.In these and other embodiments, such electronic or electrical signal maycomprise a general purpose input/output signal (GPIO) associated with aninput signal to which haptic feedback is given (e.g., a capacitive touchscreen sensor or other capacitive sensor to which haptic feedback isprovided). For purposes of clarity and exposition in this disclosure,the term “force” as used herein may refer not only to force, but tophysical quantities indicative of force or analogous to force, such as,but not limited to, pressure and touch.

Linear resonant actuator 107 may be housed within enclosure 101, and mayinclude any suitable system, device, or apparatus for producing anoscillating mechanical force across a single axis. For example, in someembodiments, linear resonant actuator 107 may rely on an alternatingcurrent voltage to drive a voice coil pressed against a moving massconnected to a spring. When the voice coil is driven at the resonantfrequency of the spring, linear resonant actuator 107 may vibrate with aperceptible force. Thus, linear resonant actuator 107 may be useful inhaptic applications within a specific frequency range. While, for thepurposes of clarity and exposition, this disclosure is described inrelation to the use of linear resonant actuator 107, it is understoodthat any other type or types of vibrational actuators (e.g., eccentricrotating mass actuators) may be used in lieu of or in addition to linearresonant actuator 107. In addition, it is also understood that actuatorsarranged to produce an oscillating mechanical force across multiple axesmay be used in lieu of or in addition to linear resonant actuator 107.As described elsewhere in this disclosure, a linear resonant actuator107, based on a signal received from integrated haptic system 112, mayrender haptic feedback to a user of mobile device 102 for at least oneof mechanical button replacement and capacitive sensor feedback.

Integrated haptic system 112 may be housed within enclosure 101, may becommunicatively coupled to force sensor 105 and linear resonant actuator107, and may include any system, device, or apparatus configured toreceive a signal from force sensor 105 indicative of a force applied tomobile device 102 (e.g., a force applied by a human finger to a virtualbutton of mobile device 102) and generate an electronic signal fordriving linear resonant actuator 107 in response to the force applied tomobile device 102. Detail of an example integrated haptic system inaccordance with embodiments of the present disclosure is depicted inFIG. 2.

Although specific example components are depicted above in FIG. 1 asbeing integral to mobile device 102 (e.g., controller 103, memory 104,force sensor 105, microphone 106, radio transmitter/receiver 108,speakers(s) 110), a mobile device 102 in accordance with this disclosuremay comprise one or more components not specifically enumerated above.For example, although FIG. 1 depicts certain user interface components,mobile device 102 may include one or more other user interfacecomponents in addition to those depicted in FIG. 1 (including but notlimited to a keypad, a touch screen, and a display), thus allowing auser to interact with and/or otherwise manipulate mobile device 102 andits associated components.

FIG. 2 illustrates a block diagram of selected components of an exampleintegrated haptic system 112A, in accordance with embodiments of thepresent disclosure. In some embodiments, integrated haptic system 112Amay be used to implement integrated haptic system 112 of FIG. 1. Asshown in FIG. 2, integrated haptic system 112A may include a digitalsignal processor (DSP) 202, a memory 204, and an amplifier 206.

DSP 202 may include any system, device, or apparatus configured tointerpret and/or execute program instructions and/or process data. Insome embodiments, DSP 202 may interpret and/or execute programinstructions and/or process data stored in memory 204 and/or othercomputer-readable media accessible to DSP 202.

Memory 204 may be communicatively coupled to DSP 202, and may includeany system, device, or apparatus configured to retain programinstructions and/or data for a period of time (e.g., computer-readablemedia). Memory 204 may include random access memory (RAM), electricallyerasable programmable read-only memory (EEPROM), a Personal ComputerMemory Card International Association (PCMCIA) card, flash memory,magnetic storage, opto-magnetic storage, or any suitable selectionand/or array of volatile or non-volatile memory that retains data afterpower to mobile device 102 is turned off.

Amplifier 206 may be electrically coupled to DSP 202 and may compriseany suitable electronic system, device, or apparatus configured toincrease the power of an input signal V_(IN) (e.g., a time-varyingvoltage or current) to generate an output signal V_(OUT). For example,amplifier 206 may use electric power from a power supply (not explicitlyshown) to increase the amplitude of a signal. Amplifier 206 may includeany suitable amplifier class, including without limitation, a Class-Damplifier.

In operation, memory 204 may store one or more haptic playbackwaveforms. In some embodiments, each of the one or more haptic playbackwaveforms may define a haptic response a(t) as a desired acceleration ofa linear resonant actuator (e.g., linear resonant actuator 107) as afunction of time. DSP 202 may be configured to receive a force signalV_(SENSE) from force sensor 105 indicative of force applied to forcesensor 105. Either in response to receipt of force signal V_(SENSE)indicating a sensed force or independently of such receipt, DSP 202 mayretrieve a haptic playback waveform from memory 204 and process suchhaptic playback waveform to determine a processed haptic playback signalV_(IN). In embodiments in which amplifier 206 is a Class D amplifier,processed haptic playback signal V_(IN) may comprise a pulse-widthmodulated signal. In response to receipt of force signal V_(SENSE)indicating a sensed force, DSP 202 may cause processed haptic playbacksignal V_(IN) to be output to amplifier 206, and amplifier 206 mayamplify processed haptic playback signal V_(IN) to generate a hapticoutput signal V_(OUT) for driving linear resonant actuator 107. Detailof an example processing system implemented by DSP 202 is depicted inFIG. 3.

In some embodiments, integrated haptic system 112A may be formed on asingle integrated circuit, thus enabling lower latency than existingapproaches to haptic feedback control. By providing integrated hapticsystem 112A as part of a single monolithic integrated circuit, latenciesbetween various interfaces and system components of integrated hapticsystem 112A may be reduced or eliminated.

As shown in FIG. 3, DSP 202 may receive diagnostic inputs from whichprocessing system 300 may monitor and adjust operation of amplifier 206in response thereto. For example, as discussed below with respect toFIG. 3, DSP 202 may receive measurements from linear resonant actuator107 to estimate the vibrational transfer function of linear resonantactuator 107. However, in some embodiments, DSP 202 may receive andmonitor one or more other diagnostic inputs, and DSP 202 may controloperation of amplifier 206 in response thereto. For example, in someembodiments, DSP 202 may monitor a current level associated with linearresonant actuator 107 and/or a voltage level associated with linearresonant actuator 107. From such measurements, DSP 202 may be able toinfer or calculate a status (e.g., status of motion) of linear resonantactuator 107. For example, from a monitored voltage and current, DSP 202may be able to employ a mathematical model of linear resonant actuator107 to estimate a displacement, velocity, and/or acceleration of linearresonant actuator 107. As another example, DSP 202 may inject ahigh-frequency signal into linear resonant actuator 107 and infer aninductance of linear resonant actuator 107 based on the current and/orvoltage responses of linear resonant actuator 107 to the injectedsignal. From the inductance, DSP 202 may be able to estimate adisplacement of linear resonant actuator 107. Based on determined statusinformation (e.g., displacement, velocity, and/or acceleration), DSP 202may control processed haptic playback signal V_(IN) for any suitablepurpose, including protecting linear resonant actuator 107 fromover-excursion that could lead to damage to linear resonant actuator 107or other components of mobile device 102. As yet another example, one ormore diagnostic inputs may be monitored to determine an operationaldrift of linear resonant actuator 107, and DSP 202 may control amplifier206 and/or processed haptic playback signal V_(IN) in order to accountfor the operational drift. As a further example, one or more diagnosticinputs may be monitored to determine temperature effects of linearresonant actuator 107 (e.g., thermally induced changes in theperformance of linear resonant actuator 107), and DSP 202 may controlamplifier 206 and/or processed haptic playback signal V_(IN) in order toaccount for the temperature effects.

FIG. 3 illustrates a block diagram of selected components of an exampleprocessing system 300 implemented by DSP 202, in accordance withembodiments of the present disclosure. As shown in FIG. 3, processingsystem 300 may include vibrational pulse processing 302, regulatedinversion 304, click-driving pulse processing 306, a comparator 308, andvibrational transfer function estimation 310. In operation, vibrationalpulse processing 302 may receive a haptic playback waveform a(t) (orrelevant parameters of such a waveform such as frequency and duration)and process such waveform to generate an intermediate signal a₁(t).Processing performed by vibrational pulse processing 302 may include,without limitation, filtering (e.g., band-pass filtering) for frequencybands of interest, equalization of haptic playback waveform a(t) toobtain a desired spectral shape, and/or temporal truncation orextrapolation of haptic playback waveform a(t). By adjusting or tuningthe temporal duration and frequency envelope of haptic playback waveforma(t), various haptic feelings as perceived by a user and/or audibilityof the haptic response may be achieved.

Regulated inversion 304 may apply an inverse transfer function ITF tointermediate signal a₁(t), either in the frequency domain orequivalently in the time domain through inverse filtering. Such inversetransfer function ITF may be generated from vibrational transferfunction estimation 310 based on actual vibrational measurements oflinear resonant actuator 107 and/or model parameters of linear resonantactuator 107. Inverse transfer function ITF may be the inverse of atransfer function that correlates output voltage signal V_(OUT) toactual acceleration of linear resonant actuator 107. By applying inversetransfer function ITF to intermediate signal a₁(t), regulated inversion304 may generate an inverted vibration signal V_(INT) in order to applyinversion to specific target vibrational click pulses to obtain anapproximation of certain desired haptic click signals to drive thevibrational actuators for the generation of haptic clicks. Inembodiments in which inverse transfer function ITF is calculated basedon measurements of linear resonant actuator 107, processing system 300may implement a closed-loop feedback system for generating output signalV_(OUT), such that processing system 300 may track vibrationalcharacteristics of linear resonant actuator 107 over the lifetime oflinear resonant actuator 107 to enable more accurate control of thehaptic response generated by integrated haptic system 112A.

In some embodiments, processing system 300 may not employ an adaptiveinverse transfer function ITF, and instead apply a fixed inversetransfer function ITF. In yet other embodiments, the haptic playbackwaveforms a(t) stored in memory 204 may already include waveformsalready adjusted by a fixed inverse transfer function ITF, in which caseprocessing system 300 may not include blocks 302 and 304, and hapticplayback waveforms a(t) may be fed directly to click-driving pulseprocessing block 306.

Click-driving pulse processing 306 may receive inverted vibration signalV_(INT) and control resonant tail suppression of inverted vibrationsignal V_(INT) in order to generate processed haptic playback signalV_(IN). Processing performed by click-driving pulse processing 306 mayinclude, without limitation, truncation of inverted vibration signalV_(INT), minimum phase component extraction for inverted vibrationsignal V_(INT), and/or filtering to control audibility of hapticplayback signal V_(IN).

Comparator 308 may compare a digitized version of force signal V_(SENSE)to a signal threshold V_(TH) related to a threshold force, andresponsive to force signal V_(SENSE) exceeding signal threshold V_(TH),may enable haptic playback signal V_(IN) to be communicated to amplifier206, such that amplifier 206 may amplify haptic playback signal V_(IN)to generate output signal V_(OUT).

Although FIG. 3 depicts comparator 308 as a simple analog comparator, insome embodiments, comparator 308 may include more detailed logic and/orcomparison than shown in FIG. 3, with the enable signal ENABLE output bycomparator 308 depending on one or more factors, parameters, and/ormeasurements in addition to or in lieu of comparison to a thresholdforce level.

In addition, although FIG. 3 depicts enable signal ENABLE beingcommunicated to click-driving pulse processing 306 and selectivelyenabling/disabling haptic playback signal YIN, in other embodiments,ENABLE signal ENABLE may be communicated to another component ofprocessing system 300 (e.g., vibrational pulse processing 302) in orderto enable, disable, or otherwise condition an output of such othercomponent.

FIG. 4 illustrates a block diagram of selected components of an exampleintegrated haptic system 112B, in accordance with embodiments of thepresent disclosure. In some embodiments, integrated haptic system 112Bmay be used to implement integrated haptic system 112 of FIG. 1. Asshown in FIG. 4, integrated haptic system 112B may include a digitalsignal processor (DSP) 402, an amplifier 406, an analog-to-digitalconverter (ADC) 408, and an ADC 410.

DSP 402 may include any system, device, or apparatus configured tointerpret and/or execute program instructions and/or process data. Insome embodiments, DSP 402 may interpret and/or execute programinstructions and/or process data stored in a memory and/or othercomputer-readable media accessible to DSP 402. As shown in FIG. 4, DSP402 may implement a prototype tonal signal generator 414, nonlinearshaping block 416, a smoothing block 418, and a velocity estimator 420.

Prototype tonal signal generator 414 may be configured to generate atonal driving signal a(t) at or near a resonance frequency f₀ of linearresonant actuator 107, and monitors an estimated velocity signal VELgenerated by velocity estimator 420 to determine an occurrence of apredefined threshold level for estimated velocity signal VEL or for anoccurrence of a peak of estimated velocity signal VEL. At the occurrenceof the predefined threshold level or peak, prototype tonal signalgenerator 414 may then cause a change of polarity of driving signala(t), which in turn may cause a moving mass of linear resonant actuator107 to experience a sudden change in velocity, creating a largeacceleration in linear resonant actuator 107, resulting in a sharphaptic feeling. Driving signal a(t) generated by prototype tonal signalgenerator 414 may be followed by nonlinear shaping block 416 that shapesthe waveform driving signal a(t) for a more efficient utilization of adriving voltage, and may be further smoothed by smoothing block 418 togenerate input voltage V_(IN).

Velocity estimator 420 may be configured to, based on a measured voltageV_(MON) of linear resonant actuator 107, a measured current I_(MON) oflinear resonant actuator 107, and known characteristics of linearresonant actuator 107 (e.g., modeling of a velocity of linear resonantactuator 107 as a function of voltage and current of linear resonantactuator 107), calculate an estimated velocity VEL of linear resonantactuator 107. In some embodiments, one or more other measurements orcharacteristics associated with linear resonant actuator 107 (e.g.,inductance) may be used in addition to or in lieu of a measured voltageand measured current in order to calculate estimated velocity VEL.

Amplifier 406 may be electrically coupled to DSP 402 and may compriseany suitable electronic system, device, or apparatus configured toincrease the power of an input signal V_(IN) (e.g., a time-varyingvoltage or current) to generate an output signal V_(OUT). For example,amplifier 406 may use electric power from a power supply (e.g., a boostpower supply, not explicitly shown) to increase the amplitude of asignal. Amplifier 406 may include any suitable amplifier class,including without limitation, a Class-D amplifier.

ADC 408 may comprise any suitable system, device, or apparatusconfigured to convert an analog current associated with linear resonantactuator 107 into a digitally equivalent measured current signalI_(MON). Similarly, ADC 410 may comprise any suitable system, device, orapparatus configured to convert an analog voltage across sense resistor412 (having a voltage indicative of an analog current associated withlinear resonant actuator 107) into a digitally equivalent measuredvoltage signal V_(MON).

In some embodiments, integrated haptic system 112B may be formed on asingle integrated circuit, thus enabling lower latency than existingapproaches to haptic feedback control.

FIG. 5 illustrates a graph depicting example waveforms of haptic drivingsignals that may be generated, in accordance with embodiments of thepresent disclosure. For example, as shown in FIG. 5, prototype tonalsignal generator 414 may generate a tonal acceleration signal a(t) whichbegins at resonant frequency f₀ and ends at a higher frequency with anaverage frequency f₁ shown in FIG. 5. Such average frequency f₁ may bechosen to be a frequency of tone that achieved a maximum accelerationlevel that avoids clipping of output voltage V_(OUT). To illustrate, themaximum achievable vibration of linear resonant actuator 107, in termsof acceleration, may be restricted. As an example, linear resonantactuator 107 may be subject to an excursion limit, which defines amaximum displacement (e.g., in both a positive and negative direction)that a moving mass of linear resonant actuator 107 may displace withoutcontacting non-moving parts of a device including linear resonantactuator 107 or otherwise causing audible buzzing and/or rattlingdistortions.

FIG. 6 illustrates a graph depicting an example transfer function ofdisplacement of linear resonant actuator 107 as a function of frequency(x(f)) at a voltage level equal to a maximum static excursion x_(MAX)occurring at low frequencies, in accordance with embodiments of thepresent disclosure. It is apparent from the graph of FIG. 6 that linearresonant actuator 107 may not be able to tolerate such a voltage level,because at resonance frequency f₀, the excursion x(f) it generates willbe over static excursion limit x_(MAX) and therefore cause clipping. Inthat sense, static excursion limit x_(MAX) may be considered the“clipping-free” excursion limit.

FIG. 7 illustrates a graph depicting an example transfer function ofacceleration of linear resonant actuator 107 as a function of frequency(a(f)) and a maximum acceleration a_(MAX) at maximum excursion x_(MAX),in accordance with embodiments of the present disclosure. In manyrespects, FIG. 7 is a translation of FIG. 6 from the displacement domainto the acceleration domain. From FIG. 7, it is seen that, below acertain frequency f₁, the maximum acceleration level linear resonantactuator 107 may generate may be restricted by the clipping-freeexcursion limit, and not by a voltage of amplifier 406. This means thatbelow the certain frequency f₁, linear resonant actuator 107 needs to bedriven at an attenuated voltage level. On the other hand, for such amaximum voltage level that nearly reaches a maximum excursion limitx_(MAX) without clipping, the maximum achievable clipping-freeacceleration level a_(MAX) is achievable not at a resonance frequencyf₀, but at a chosen frequency f₁, which is above resonance.

Such chosen frequency f₁ may provide a good choice of initialization forthe design of haptic clicks and for the timing (e.g., a passage of timeT1, as shown in FIG. 3) of the change in polarity of the accelerationsignal a(t) to achieve an acceleration peak. However, in addition to thespecific example of a very short pulse described above, other examplesof waveforms with longer cycles may be used, as well as other logics todetermine a passage of time T1 (e.g., time T1) for changing polarity ofthe acceleration signal a(t), the effect of which is to force the movingmass to rapidly change velocity and generate a large acceleration peak.The larger the change rate of velocity, the higher the acceleration peaklinear resonant actuator 107 may create.

FIG. 8 illustrates a block diagram of selected components of anotherexample integrated haptic system 112C, in accordance with embodiments ofthe present disclosure. In some embodiments, integrated haptic system112C may be used to implement integrated haptic system 112 of FIG. 1. Asshown in FIG. 8, integrated haptic system 112C may include a detector808 and an amplifier 806.

Detector 808 may include any system, device, or apparatus configured todetect a signal (e.g., V_(SENSE)) indicative of a force. In someembodiments, such signal may be a signal generated by a force sensor. Inother embodiments, such signal may comprise a GPIO signal indicative ofa force applied to a force sensor. In some embodiments, detector 808 maysimply detect whether GPIO signal is asserted or deasserted. In otherembodiments, signal V_(SENSE) may indicate a magnitude of force appliedand may apply logic (e.g., analog-to-digital conversion where signalV_(SENSE) is analog, comparison to a threshold force level, and/or logicassociated with other measurements or parameters). In any event,responsive to signal V_(SENSE) indicating a requisite force, detector808 may enable amplifier 806 (e.g., by enabling its power supply orpower supply boost mode) such that amplifier 806 may amplify hapticplayback signal V_(IN) (which may be generated by a component internalto or external to integrated haptic system 112C) to generate outputsignal V_(OUT). Accordingly, amplifier 806 may be maintained in alow-power or inactive state until a requisite input signal is receivedby integrated haptic system 112C, at which amplifier may be powered upor effectively switched on. Allowing for amplifier 806 to be kept in alow-power or inactive state until a requisite input is received mayresult in a considerable reduction in power consumption of a circuit,and enable “always-on” functionality for a device incorporatingintegrated haptic system 112C.

In alternative embodiments, detector 808 may be configured to,responsive to a requisite signal V_(SENSE), enable haptic playbacksignal V_(IN) to be communicated to amplifier 806, such that amplifier806 may amplify haptic playback signal V_(IN) to generate output signalV_(OUT).

In some embodiments, all or a portion of detector 808 may be implementedby a DSP.

Amplifier 806 may be electrically coupled to detector 808 and maycomprise any suitable electronic system, device, or apparatus configuredto increase the power of an input signal V_(IN) (e.g., a time-varyingvoltage or current) to generate an output signal V_(OUT). For example,amplifier 806 may use electric power from a power supply (not explicitlyshown) to increase the amplitude of a signal. Amplifier 806 may includeany suitable amplifier class, including without limitation, a Class-Damplifier.

In some embodiments, integrated haptic system 112C may be formed on asingle integrated circuit, thus enabling lower latency than existingapproaches to haptic feedback control.

FIG. 9 illustrates a block diagram of selected components of an exampleintegrated haptic system 112D, in accordance with embodiments of thepresent disclosure. In some embodiments, integrated haptic system 112Dmay be used to implement integrated haptic system 112 of FIG. 1. Asshown in FIG. 9, integrated haptic system 112D may include a digitalsignal processor (DSP) 902, an amplifier 906, and an applicationsprocessor interface 908.

DSP 902 may include any system, device, or apparatus configured tointerpret and/or execute program instructions and/or process data. Insome embodiments, DSP 902 may interpret and/or execute programinstructions and/or process data stored in a memory and/or othercomputer-readable media accessible to DSP 902.

Amplifier 906 may be electrically coupled to DSP 902 and may compriseany suitable electronic system, device, or apparatus configured toincrease the power of an input signal V_(IN) (e.g., a time-varyingvoltage or current) to generate an output signal V_(OUT). For example,amplifier 906 may use electric power from a power supply (not explicitlyshown) to increase the amplitude of a signal. Amplifier 906 may includeany suitable amplifier class, including without limitation, a Class-Damplifier.

Applications processor interface 908 may be communicatively coupled toDSP 902 and an applications processor (e.g., controller 103 of FIG. 1)external to integrated haptic system 112D. Accordingly, applicationsprocessor interface 908 may enable communication between integratedhaptic system 112D and an application executing on an applicationsprocessor.

In some embodiments, integrated haptic system 112D may be formed on asingle integrated circuit, thus enabling lower latency than existingapproaches to haptic feedback control.

In operation, DSP 902 may be configured to receive a force signalV_(SENSE) from force sensor 105 indicative of force applied to forcesensor 105. In response to receipt of force signal V_(SENSE) indicatinga sensed force, DSP 902 may generate a haptic playback signal V_(IN) andcommunicate haptic playback signal V_(IN) to amplifier 906. In addition,in response to the receipt of force signal V_(SENSE) indicating a sensedforce, DSP 902 may communicate an activity notification to anappropriate applications processor via applications processor interface908. DSP 902 may further be configured to receive communications from anapplications processor via applications processor interface 908 andgenerate (in addition to and in lieu of generation responsive to receiptof force signal V_(SENSE)) haptic playback signal V_(IN) and communicatehaptic playback signal V_(IN) to amplifier 906.

As the output for an initial haptic feedback response can be generatedby the integrated haptic system 112D, integrated haptic system 112D maybe configured to provide a low-latency response time for the generationof immediate haptic feedback. Subsequent to the initial feedback beinggenerated, the control of additional haptic feedback signals may bedetermined by a separate applications processor arranged to interfacewith integrated haptic system 112D. By offloading the control ofsubsequent haptic driver signals to a separate applications processor,integrated haptic system 112D may be optimized for low-power,low-latency performance, to generate the initial haptic feedbackresponse. The initial output signal V_(OUT) may be provided at arelatively low resolution, resulting in the generation of a relativelysimplified haptic feedback response. For example, the initial outputsignal V_(OUT) may be provided as a globalized feedback response.Subsequent to the initial response, the applications processor may beused to generate more detailed haptic feedback outputs, for exampleproviding for localized haptic feedback responses, which may requireincreased processing resources when compared with the relativelystraightforward generation of a globalized haptic feedback response.

As another example, in an effort to minimize the power consumption ofmobile device 102 for always-on operation, the integrated haptic system112D may be configured to monitor a single input from a singleforce-sensing transducer (e.g., force sensor 105) to detect a userinput. However, once an initial user input has been detected, the powerand resources of an applications processor may be used to provide moredetailed signal analysis and response. The applications processor may beconfigured to receive input signals from multiple force-sensingtransducers, and/or to generate output signals for multiple haptictransducers.

FIG. 10 illustrates a block diagram of selected components of an exampleintegrated haptic system 112E, in accordance with embodiments of thepresent disclosure. In some embodiments, integrated haptic system 112Emay be used to implement integrated haptic system 112 of FIG. 1. Asshown in FIG. 10, integrated haptic system 112E may include a digitalsignal processor (DSP) 1002, an amplifier 1006, and a signal combiner1008.

DSP 1002 may include any system, device, or apparatus configured tointerpret and/or execute program instructions and/or process data. Insome embodiments, DSP 1002 may interpret and/or execute programinstructions and/or process data stored in a memory and/or othercomputer-readable media accessible to DSP 1002.

Amplifier 1006 may be electrically coupled to DSP 1002 (e.g., via signalcombiner 1008) and may comprise any suitable electronic system, device,or apparatus configured to increase the power of an input signal V_(IN)(e.g., a time-varying voltage or current) to generate an output signalV_(OUT). For example, amplifier 1006 may use electric power from a powersupply (not explicitly shown) to increase the amplitude of a signalAmplifier 1006 may include any suitable amplifier class, includingwithout limitation, a Class-D amplifier.

Signal combiner 1008 may be interfaced between DSP 1002 and amplifier1006 and may comprise any system, device, or apparatus configured tocombine a signal generated by DSP 1002 and a vibration alert signalreceived from a component external to integrated haptic system 112E.

In some embodiments, integrated haptic system 112E may be formed on asingle integrated circuit, thus enabling lower latency than existingapproaches to haptic feedback control.

In operation, DSP 1002 may be configured to receive a force signalV_(SENSE) from force sensor 105 indicative of force applied to forcesensor 105. In response to receipt of force signal V_(SENSE) indicatinga sensed force, DSP 1002 may generate an intermediate haptic playbacksignal V_(INT). Signal combiner 1008 may receive intermediate hapticplayback signal V_(INT) and mix intermediate haptic playback signalV_(INT) with another signal (e.g., the vibration alert signal) receivedby integrated haptic system 112E to generate a haptic playback signalV_(IN) and communicate haptic playback signal V_(IN) to amplifier 1006.Accordingly, a haptic signal generated responsive to a force (e.g.,intermediate haptic playback signal V_(INT)) may be mixed with a furthersignal (e.g., the vibration alert signal), to provide a composite signal(e.g., haptic playback signal V_(IN)) for linear resonant actuator 107.For example, the signal to generate a pure haptic feedback response maybe mixed with a signal used to generate a vibratory notification oralert, for example as notification of an incoming call or message. Suchmixing would allow for a user to determine that an alert has beenreceived at the same time as feeling a haptic feedback response. Asshown in FIG. 10, signal combiner 1008 may perform mixing on an inputsignal used as input to the amplifier 1006. However, in otherembodiments, a signal combiner may perform mixing on an output signalfor driving linear resonant actuator 107.

FIG. 11 illustrates a block diagram of selected components of an exampleintegrated haptic system 112F, in accordance with embodiments of thepresent disclosure. In some embodiments, integrated haptic system 112Fmay be used to implement integrated haptic system 112 of FIG. 1. Asshown in FIG. 11, integrated haptic system 112F may include a digitalsignal processor (DSP) 1102, a detector 1104, an amplifier 1106, asampling control 1108, and a sensor bias generator 1112.

DSP 1102 may include any system, device, or apparatus configured tointerpret and/or execute program instructions and/or process data. Insome embodiments, DSP 1102 may interpret and/or execute programinstructions and/or process data stored in a memory and/or othercomputer-readable media accessible to DSP 1102.

Detector 1104 may include any system, device, or apparatus configured todetect a signal (e.g., V_(SENSE)) indicative of a force. In someembodiments, such signal may be a signal generated by a force sensor. Inother embodiments, such signal may comprise a GPIO signal indicative ofa force applied to a force sensor. In some embodiments, detector 1104may simply detect whether GPIO signal is asserted or deasserted. Inother embodiments, signal V_(SENSE) may indicate a magnitude of forceapplied and may apply logic (e.g., analog-to-digital conversion wheresignal V_(SENSE) is analog, comparison to a threshold force level,and/or logic associated with other measurements or parameters). In anyevent, responsive to signal V_(SENSE) indicating a requisite force,detector 1104 may communicate one or more signals to DSP 1102 indicativeof signal V_(SENSE). In some embodiments, all or a portion of detector1104 may be implemented by DSP 1102.

Amplifier 1106 may be electrically coupled to DSP 1102 and may compriseany suitable electronic system, device, or apparatus configured toincrease the power of an input signal V_(IN) (e.g., a time-varyingvoltage or current) to generate an output signal V_(OUT). For example,amplifier 1106 may use electric power from a power supply (notexplicitly shown) to increase the amplitude of a signal. Amplifier 1106may include any suitable amplifier class, including without limitation,a Class-D amplifier.

Sampling control 1108 may be communicatively coupled to DSP 1102 and maycomprise any suitable electronic system, device, or apparatus configuredto selectively enable force sensor 105 and/or components of integratedhaptic system 112F, as described in greater detail below.

Sensor bias 1112 may be communicatively coupled to sampling control 1108and may comprise any suitable electronic system, device, or apparatusconfigured to generate an electric bias (e.g., bias voltage or biascurrent) for force sensor 105, as described in greater detail below.

In some embodiments, integrated haptic system 112F may be formed on asingle integrated circuit, thus enabling lower latency than existingapproaches to haptic feedback control.

In operation, DSP 1102/detector 1104 may be configured to receive aforce signal V_(SENSE) from force sensor 105 indicative of force appliedto force sensor 105. In response to receipt of force signal V_(SENSE)indicating a sensed force, DSP 1102 may generate a haptic playbacksignal V_(IN) and communicate haptic playback signal V_(IN) to amplifier1106, which is amplified by amplifier 1106 to generate output voltageV_(OUT).

In addition, DSP 1102 may be configured to receive one or more timersignals (either from timing signals generated within integrated hapticsystem 112F or external to integrated haptic system 112F) and basedthereon, generate signals to sampling control 1108. In turn, samplingcontrol 1108 may selectively enable and disable one or more componentsof an input path of integrated haptic system 112F, including withoutlimitation detector 1104, force sensor 105, a data interface ofintegrated haptic system 112F, a switch matrix of integrated hapticsystem 112F, an input amplifier of integrated haptic system 112F, and/oran analog-to-digital converter of integrated haptic system 112F. Asshown in FIG. 11, sampling control 1108 may selectively enable anddisable force sensor 105 by controlling an electrical bias for forcesensor 105 generated by sensor bias 1112. As a result, DSP 1102 andsampling control 1108 may duty cycle durations of time in which forcesensor 105, detector 1104, and/or other components of integrated hapticsystem 112F are active, potentially reducing power consumption of asystem comprising integrated haptic system 112F.

Although the foregoing figures and descriptions thereof addressintegrated haptic systems 112A-112F as being representative ofparticular embodiments, is it understood that all or a portion of one ormore of integrated haptic systems 112A-112F may be combined with all ora portion of another of integrated haptic systems 112A-112F, assuitable.

In addition, in many of the figures above, a DSP is shown generating ahaptic playback signal V_(IN) which may be amplified by an amplifier togenerate an output voltage V_(OUT). For purposes of clarity andexposition, digital-to-analog conversion of signals in the output signalpath of integrated haptic systems 112A-112F have been omitted from thedrawings, but it is understood that digital-to-analog converters may bepresent in integrated haptic systems 112A-112F to perform any necessaryconversions from a digital domain to an analog domain.

This disclosure encompasses all changes, substitutions, variations,alterations, and modifications to the example embodiments herein that aperson having ordinary skill in the art would comprehend. Similarly,where appropriate, the appended claims encompass all changes,substitutions, variations, alterations, and modifications to the exampleembodiments herein that a person having ordinary skill in the art wouldcomprehend. Moreover, reference in the appended claims to an apparatusor system or a component of an apparatus or system being adapted to,arranged to, capable of, configured to, enabled to, operable to, oroperative to perform a particular function encompasses that apparatus,system, or component, whether or not it or that particular function isactivated, turned on, or unlocked, as long as that apparatus, system, orcomponent is so adapted, arranged, capable, configured, enabled,operable, or operative.

All examples and conditional language recited herein are intended forpedagogical objects to aid the reader in understanding the invention andthe concepts contributed by the inventor to furthering the art, and areconstrued as being without limitation to such specifically recitedexamples and conditions. Although embodiments of the present inventionshave been described in detail, it should be understood that variouschanges, substitutions, and alterations could be made hereto withoutdeparting from the spirit and scope of the disclosure.

1. (canceled)
 2. The integrated haptic system of claim 17, furthercomprising a memory communicatively coupled to the digital signalprocessor, and wherein the digital signal processor is furtherconfigured to: retrieve from the memory a haptic playback waveform; andprocess the haptic playback waveform to generate the haptic playbacksignal.
 3. The integrated haptic system of claim 2, wherein the hapticplayback waveform defines a haptic response as an acceleration as afunction of time.
 4. The integrated haptic system of claim 3, whereinthe digital signal processor generates the haptic playback signal torender haptic feedback for at least one of mechanical button replacementand capacitive sensor feedback.
 5. The integrated haptic system of claim4, wherein the digital signal processor applies an inverse transferfunction to the haptic playback waveform in order to generate the hapticplayback signal, wherein the inverse transfer function is an inverse ofa transfer function defining a relationship between a voltage applied tothe vibrational actuator and an acceleration of the vibrational actuatorresponsive to the voltage applied.
 6. The integrated haptic system ofclaim 5, wherein the digital signal processor controls the hapticplayback signal in a closed feedback loop whereby the digital signalprocessor adapts the inverse transfer function based on at least one ofmodeled parameters and measured parameters of the vibrational actuator.7. The integrated haptic system of claim 2, wherein the digital signalprocessor applies an inverse transfer function to the haptic playbackwaveform in order to generate the haptic playback signal, wherein theinverse transfer function is an inverse of a transfer function defininga relationship between a voltage applied to the vibrational actuator andan acceleration of the vibrational actuator responsive to the voltageapplied.
 8. The integrated haptic system of claim 7, wherein the digitalsignal processor controls the haptic playback signal in a closedfeedback loop whereby the digital signal processor adapts the inversetransfer function based on at least one of modeled parameters andmeasured parameters of the vibrational actuator.
 9. The integratedhaptic system of claim 17, wherein: the input signal is a force sensorsignal generated by the force sensor; and the digital signal processorcommunicates the haptic playback signal to the amplifier in response toreceipt of the force sensor signal.
 10. The integrated haptic system ofclaim 17, wherein: the input is a force sensor signal generated by theforce sensor; and the digital signal processor communicates the hapticplayback signal to the amplifier in response to the force sensor signalexceeding a threshold.
 11. The integrated haptic system of claim 17,wherein the digital signal processor generates the haptic playbacksignal to render haptic feedback for at least one of mechanical buttonreplacement and capacitive sensor feedback.
 12. The integrated hapticsystem of claim 17, wherein the digital signal processor controls thehaptic playback signal in a closed feedback loop whereby the digitalsignal processor adapts its processing based on at least one of modeledparameters and measured parameters of the vibrational actuator.
 13. Theintegrated haptic system of claim 17, wherein the digital signalprocessor is further configured to, responsive to a condition forchanging a polarity of the haptic playback signal, change the polarityof the haptic playback signal.
 14. The integrated haptic system of claim13, wherein the digital signal processor is further configured tocalculate an estimated velocity based on one or more measured electricalparameters of the vibrational actuator, wherein the condition forchanging the polarity of the haptic playback signal comprises theestimated velocity reaching a threshold velocity level or velocity peak.15. The integrated haptic system of claim 14, wherein measuredelectrical parameters comprise one or more of a voltage and a current.16. The integrated haptic system of claim 13, wherein the condition forchanging the polarity of the haptic playback signal comprises thepassage of a time equal to an inverse of a frequency at which a maximumclipping-free acceleration level is obtainable.
 17. An integrated hapticsystem of claim comprising: a digital signal processor configured to:receive an input signal indicative of a force applied to a force sensor;and generate a haptic playback signal responsive to the input signal;and an amplifier communicatively coupled to the digital signalprocessor, integrated with the digital signal processor into theintegrated haptic system, and configured to amplify the haptic playbacksignal and drive a vibrational actuator communicatively coupled to theamplifier with the haptic playback signal as amplified by the amplifier;wherein the digital signal processor is further configured to: monitorone or more diagnostic inputs indicative of a status of the vibrationalactuator; and control at least one of operation of the amplifier and thehaptic playback signal responsive to monitoring of the one or morediagnostic inputs.
 18. The integrated haptic system of claim 17, whereinthe one or more diagnostic inputs are indicative of one or more of acurrent, a voltage, and an inductance of the vibrational actuator. 19.The integrated haptic system of claim 17, wherein the digital signalprocessor is further configured to: determine a displacement of thevibrational actuator based on the one or more diagnostic inputs; andcontrol the haptic playback signal to prevent the vibrational actuatorfrom exceeding a displacement limit.
 20. The integrated haptic system ofclaim 17, wherein the digital signal processor is further configured to:determine operational drift of the vibrational actuator based on the oneor more diagnostic inputs; and control the haptic playback signal toaccount for the operational drift.
 21. The integrated haptic system ofclaim 17, wherein the digital signal processor is further configured to:determine temperature effects of the vibrational actuator based on theone or more diagnostic inputs; and control the haptic playback signal toaccount for the temperature effects.
 22. The integrated haptic system ofclaim 17, further comprising an applications processor interfaceinterfaced between the digital signal processor and an applicationsprocessor external to the integrated haptic system, wherein the digitalsignal processor is further configured to communicate an activitynotification to the applications processor via the applicationsprocessor interface responsive to the force.
 23. The integrated hapticsystem of claim 17, further comprising an applications processorinterface interfaced between the digital signal processor and anapplications processor external to the integrated haptic system, whereinthe digital signal processor is further configured to: receivecommunications from the applications processor via the applicationsprocessor interface; and modify the haptic playback signal responsive tothe communications.
 24. The integrated haptic system of claim 17,wherein the integrated haptic system is further configured to mix anintermediate haptic playback signal generated by the digital signalprocessor with another signal received by the integrated haptic systemto generate the haptic playback signal.
 25. The integrated haptic systemof claim 17, wherein the digital signal processor is further configuredto selectively enable and disable the amplifier based on the inputsignal.
 26. The integrated haptic system of claim 17, wherein theintegrated haptic system is integral to one of a mobile phone, personaldigital assistant, and game controller.
 27. The integrated haptic systemof claim 17, further comprising a sampling controller communicativelycoupled to the digital signal processor and configured to generate aduty-cycling signal to duty-cycle the force sensor in order to reduce anactive duration of the force sensor.
 28. The integrated haptic system ofclaim 27, wherein: the input signal is a force sensor signal generatedby the force sensor; and the integrated haptic system further comprisesan input path arranged to communicate the force sensor signal to thedigital signal processor, and wherein the sampling controller is furtherconfigured to generate a second duty-cycling signal to duty-cycle to oneor more components of the input path to reduce an active duration of theinput path.
 29. The integrated haptic system of claim 28, wherein theone or more components comprise one or more of a detector, a datainterface, a switch matrix, an input path amplifier, and ananalog-to-digital converter.
 30. The integrated haptic system of claim17, wherein the digital signal processor and the amplifier are formed onand integral to a single integrated circuit.
 31. (canceled)
 32. Themethod of claim 47, further comprising: retrieving, by the digitalsignal processor from a memory communicatively coupled to the digitalsignal processor, a haptic playback waveform; and processing, by thedigital signal processor, the haptic playback waveform to generate thehaptic playback signal.
 33. The method of claim 32, wherein the hapticplayback waveform defines a haptic response as an acceleration as afunction of time.
 34. The method of claim 33, wherein the digital signalprocessor generates the haptic playback signal to render haptic feedbackfor at least one of mechanical button replacement and capacitive sensorfeedback.
 35. The method of claim 34, further comprising applying, bythe digital signal processor, an inverse transfer function to the hapticplayback waveform in order to generate the haptic playback signal,wherein the inverse transfer function is an inverse of a transferfunction defining a relationship between a voltage applied to avibrational actuator and an acceleration of the vibrational actuatorresponsive to the voltage applied.
 36. The method of claim 35, furthercomprising controlling, by the digital signal processor, the hapticplayback signal in a closed feedback loop whereby the digital signalprocessor adapts the inverse transfer function based on at least one ofmodeled parameters and measured parameters of the vibrational actuator.37. The method of claim 36, further comprising applying, by the digitalsignal processor, the inverse transfer function to the haptic playbackwaveform in order to generate the haptic playback signal, wherein theinverse transfer function is an inverse of a transfer function defininga relationship between a voltage applied to the vibrational actuator andan acceleration of the vibrational actuator responsive to the voltageapplied.
 38. The method of claim 37, further comprising controlling, bythe digital signal processor, the haptic playback signal in a closedfeedback loop whereby the digital signal processor adapts the inversetransfer function based on at least one of modeled parameters andmeasured parameters of the vibrational actuator.
 39. The method of claim47, wherein: the input signal is a force sensor signal generated by theforce sensor; and the method further comprises communicating, by thedigital signal processor, the haptic playback signal to the amplifier inresponse to receipt of the force sensor signal.
 40. The method of claim47, wherein: the input signal is a force sensor signal generated by theforce sensor; and the method further comprises communicating, by thedigital signal processor, the haptic playback signal to the amplifier inresponse to the force sensor signal exceeding a threshold.
 41. Themethod of claim 47, wherein the digital signal processor generates thehaptic playback signal to render haptic feedback for at least one ofmechanical button replacement and capacitive sensor feedback.
 42. Themethod of claim 47, further comprising controlling, by the digitalsignal processor, the haptic playback signal in a closed feedback loopwhereby the digital signal processor adapts its processing based on atleast one of modeled parameters and measured parameters of a vibrationalactuator.
 43. The method of claim 47, further comprising changing, bythe digital signal processor, a polarity of the haptic playback signalresponsive to a condition for changing the polarity of the hapticplayback signal.
 44. The method of claim 43, further comprisingcalculating, by the digital signal processor, estimated velocity basedon one or more measured electrical parameters of a vibrational actuator,wherein the condition for changing the polarity of the haptic playbacksignal comprises the estimated velocity reaching a threshold velocitylevel or velocity peak.
 45. The method of claim 44, wherein measuredelectrical parameters comprise one or more of a voltage and a current.46. The method of claim 43, wherein the condition for changing thepolarity of the haptic playback signal comprises the passage of a timeequal to an inverse of a frequency at which a maximum clipping-freeacceleration level is obtainable.
 47. A method comprising: receiving, bya digital signal processor, an input signal indicative of a forceapplied to a force sensor; generating, by the digital signal processor,a haptic playback signal responsive to the input signal; driving, withan amplifier communicatively coupled to the digital signal processor andintegrated with the digital signal processor into an integrated hapticsystem, the haptic playback signal as amplified by the amplifier;monitoring, by the digital signal processor, one or more diagnosticinputs indicative of a status of a vibrational actuator; andcontrolling, by the digital signal processor, at least one of operationof the amplifier and the haptic playback signal responsive to monitoringof the one or more diagnostic inputs.
 48. The method of claim 47,wherein the one or more diagnostic inputs are indicative of one or moreof a current, a voltage, and an inductance of the vibrational actuator.49. The method of claim 47, further comprising, by the digital signalprocessor: determining a displacement of the vibrational actuator basedon the one or more diagnostic inputs; and controlling the hapticplayback signal to prevent the vibrational actuator from exceeding adisplacement limit.
 50. The method of claim 47, further comprising, bythe digital signal processor: determining operational drift of thevibrational actuator based on the one or more diagnostic inputs; andcontrolling the haptic playback signal to account for the operationaldrift.
 51. The method of claim 47, further comprising, by the digitalsignal processor: determining temperature effects of the vibrationalactuator based on the one or more diagnostic inputs; and controlling thehaptic playback signal to account for the temperature effects.
 52. Themethod of claim 47, further comprising communicating, by the digitalsignal processor, an activity notification to an applications processorexternal to the integrated haptic system via an applications processorinterface responsive to the force, wherein the applications processorinterface is interfaced between the digital signal processor and theapplications processor.
 53. The method of claim 47, further comprising,by the digital signal processor: receiving communications from anapplications processor external to the integrated haptic system via anapplications processor interface, wherein the applications processorinterface is interfaced between the digital signal processor and theapplications processor; and modifying the haptic playback signalresponsive to the communications.
 54. The method of claim 47, furthercomprising mixing an intermediate haptic playback signal generated bythe digital signal processor with another signal received by theintegrated haptic system to generate the haptic playback signal.
 55. Themethod of claim 47, further comprising selectively enabling anddisabling the amplifier based on the input signal.
 56. The method ofclaim 47, further comprising generating a duty-cycling signal toduty-cycle the force sensor in order to reduce an active duration of theforce sensor.
 57. The method of claim 56, wherein: the input signal is aforce sensor signal generated by the force sensor; and the methodfurther comprises generating a second duty-cycling signal to duty-cycleto one or more components of an input path of the integrated hapticsystem to reduce an active duration of the input path, wherein the inputpath is arranged to communicate the force sensor signal to the digitalsignal processor.
 58. The method of claim 57, wherein the one or morecomponents comprise one or more of a detector, a data interface, aswitch matrix, an input path amplifier, and an analog-to-digitalconverter.
 59. The method of claim 47, wherein the digital signalprocessor and the amplifier are formed on and integral to a singleintegrated circuit.
 60. An article of manufacture comprising: anon-transitory computer-readable medium; and computer-executableinstructions carried on the computer-readable medium, the instructionsreadable by a processor, the instructions, when read and executed, forcausing the processor to: receive an input signal indicative of a forceapplied to a force sensor; and generate a haptic playback signalresponsive to the input signal, such that an amplifier communicativelycoupled to the processor and integrated with the digital signalprocessor into an integrated haptic system, amplifies and drives thehaptic playback signal.